Coumarin is a chemical compound which is found naturally in some plants, although it can be synthetically produced as well. It has a distinctive odor which has led people to use it as a food additive and ingredient in perfume. Due to concerns about coumarin as a potential liver and kidney toxin, its use as a food additive is heavily restricted, although it is perfectly safe to eat foods which naturally contain the compound.
The chemical name for coumarin is benzopyrone. The distinctive sweet odor reminds many people of freshly cut grass or hay, and it has been used in perfumes since the late 1800s. In a pure form, this compound has a crystalline structure, and it is said to taste faintly like vanilla. When ingested, it acts as a blood thinner, and it also appears to be effective in treating some tumors. Coumarin has fungicidal properties as well. However, other much safer substances can be used for all of these purposes, although the compound is sometimes used in combination with other blood thinners for medical treatment.